1. Field
The described technology relates generally to a rechargeable battery.
2. Description of the Related Art
Recent technological developments and increase in demand for mobile devices have facilitated increase in demand for rechargeable batteries as an energy source. A cylindrical rechargeable battery usually includes an electrode assembly formed by placing electrodes on two surfaces of a separator and winding the electrodes and the separator in a form of a jelly roll, a case accommodating the electrode assembly, and a cap assembly electrically connected to the electrode assembly and sealing an opening side of the case.
The cap assembly may be coupled to the case by inserting a gasket between the opening side of the case and the cap assembly by a crimping process. In other words, the case holds an outer circumference of the cap assembly with a clamping part connected to a beading part positioned on the side of the opening of the case and depressed toward the center of the case.
At an initial stage of a beading process of forming the beading part, a centering process of matching a sleeve contacting the sides of the opening of the case, and the center of the case is performed. In other words, the sleeve and the center of the case are matched to each other by making the sleeve contact the sides of the opening of the case, and then rotating the case accordingly.
However, in this case, a trimming cross-section of the opening side of the case, which is in contact with the sleeve, may be worn out. Accordingly, even though an antirust processing is performed on the opening side of the case, the trimming cross-section may become worn out, thereby losing an antirust effect.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.